How Much Do You Know About Abrasive Paper Grit!

After completing any woodworking project, the next important step is sanding. Whether you choose to use any type of electric sander or manual sanding, you need to choose the right sandpaper type and grit. Using the wrong abrasive paper grit can cause irreversible damage to your work, so this step is particularly important.

Choose the right sandpaper grit

Abrasive paper grit is graded based on the number of abrasive particles per square inch that make up the abrasive paper grit. The lower the number, the coarser the grit. Sandpaper is typically categorized as coarse (40 to 60 grit), medium (80 to 120 grit), fine (150 to 180 grit), very fine (220 to 240 grit), extra fine (280 to 320 grit), and finer than extra fine (360 grit and above). Sanding with progressively finer grits can remove scratches left by coarser grit sandpaper and ultimately leave a smooth surface.

You might ask, "Why can't I just sand the entire process with fine-grit sandpaper?" There's nothing saying you can't, but coarse-grit sandpaper will quickly remove excess rough material, and then you can sand with finer grits to make the surface smoother, making the whole sanding process easier and faster. Plus, almost all experienced woodworkers will tell beginners that sanding is a task best performed quickly.

Grade your abrasive paper grit

There are two main types of abrasive paper grit: commercial and industrial. The difference lies in its composition, namely the material used for the grit, the backing material (paper), and the glue used to hold the grit on the paper. Industrial-grade uses higher-quality materials for all three components.

In addition, you may come across sandpapers referred to as "open coat" or "closed coat". The difference is that closed coat sandpaper has grit particles grouped more tightly, while open coat sandpaper has larger gaps between the particles. As a general rule, open coat sandpaper is typically better for woodworking because it is less prone to clogging, especially when working with softer woods that contain more resin.

Sandpaper abrasive types

There are five main types of abrasive paper grit to choose from, but not all sandpapers are beneficial for woodworking. Garnet paper is lightweight and typically pale yellow in color. Garnet paper is easy to break down and is rarely used in woodworking.

Aluminum oxide is another common type of abrasive paper grit used for woodworking projects. It is the most commonly used paper type for electric sanders. Aluminum oxide is more durable than garnet paper but doesn't leave as good of a finish.

Silicon carbide paper is typically dark gray or even black. This type of paper is mainly used for precision grinding of metals or for "wet sanding" using water as a lubricant. While some advanced surface treatments use silicon carbide paper, it is generally not used for woodworking.

Finally, ceramic abrasive paper grit is made from some of the toughest abrasive materials and can remove a significant amount of rough material in a short amount of time. Ceramic paper is usually used for belt sanders, but it is sometimes used for hand sanding wood as well. It tends to leave a very rough surface, so caution must be exercised when using ceramic sandpaper, especially on veneer or painted surfaces, as it can quickly cut through the finish and damage the workpiece itself.